NO. I FUEL ECONOMY — MITMAN 9 



subject the whole operation to definite chemical control. These three 

 will now be taken up in turn for discussion. 



Steam Flow Measurement 



Experience reveals the surprising fact that the average operator, 

 more particularly the smaller operator, has not the remotest con- 

 ception as to how much steam he is securing, in other words, 

 whether he is operating on an efficient basis of seven or eight pounds 

 of steam per pound of coal or whether he is getting only four or five 

 pounds. Accordingly, taken by itself a steam flow indicator is a first 

 requisite to enable the operator to be cognizant of conditions and the 

 possible room for improvement. Its further function as an adjunct 

 to the fitting control of furnace practice has already been brought out. 



The steam flow meter is applied to the steam outlet of the boiler 

 and in its simpler form will indicate on its dial the momentary output 

 of steam. There are several types of flow meters made, all of which, 

 however, are designed fundamentally on the Pitot tube or the Venturi 

 tube principle. Whatever the type, the meter is installed in the steam 

 line and the steam in passing through the mechanism produces a 

 dififerential pressure which is proportional to the square of its velocity 

 or rate of flow. Any change in pressure actuates the indicating hand 

 on the meter dial, the readings on which may be in pounds per hour 

 or in horsepower. 



Flue Gas Analysis 



Thanks to the efforts of scientists, the chemistry of gases, and 

 particularly their analysis, has been resolved into quite a simple pro- 

 cedure. There are several ways in which gases may be analyzed, 

 depending upon one or another of the properties of the individual 

 compounds composing them as, for instance, the differences in refrac- 

 tive power of the constituents, and again, the power of certain 

 chemical reagents to select and absorb one of the several compounds. 

 A familiar appHcation of this latter principle is the gas mask used 

 during the war, in which a certain reagent is used to absorb the 

 poisonous constituent of the war gas before the air containing it is 

 breathed into the lungs. It is this same principle that is most gen- 

 erally used in the analysis of flue gases, and while the several types 

 of apparatus used to make analyses by this method may vary as to 

 detail, they are simply modifications of the apparatus devised about 

 50 years ago by the French scientist, Orsat. 



We have seen earlier that the significant gases which may pass up 

 the stack of a furnace are carbon dioxide, oxygen, and carbon mon- 



